Downhole Hydraulic Fracturing Tool

ABSTRACT

A downhole tool for injecting fluid in a wellbore intersecting a subterranean formation. The tool can include a housing, a piston assembly moveably received in a chamber in the housing and dividing the chamber into an extension cavity and a retraction cavity, a rod assembly moveable within the housing and including a conduit, a nozzle in fluid communication with the conduit. The tool can release fluid in a cyclical pattern powered by pressurized fluid flowing through the conduit or a power source such as a pump with control lines in fluid communication with the cavities.

BACKGROUND

This section is intended to provide background information to facilitatea better understanding of the various aspects of the describedembodiments. Accordingly, it should be understood that these statementsare to be read in this light and not as admissions of prior art.

Hydrocarbon-producing wells often are stimulated by hydraulic fracturingoperations. A fracturing fluid may be introduced into a portion of asubterranean formation penetrated by a wellbore at a pressure sufficientto create or enhance fractures in the formation. Stimulating or treatingthe formation in such ways increases hydrocarbon production from thewell.

In some hydraulic fracturing operations, the fracturing fluid enters thesubterranean formation through one or more perforations. Theseperforations may be formed using a variety of techniques includingjetting a fluid or detonating explosive charges into the casing orformation. Jetting releases a fluid through a nozzle at high pressureproducing a narrow stream that erodes or washes away formation or casingmaterials. The fluid is generally supplied through the use of pumps orother pressurization equipment at the surface of the wellbore. Explosivecharges can be carried using wireline or tubing, depending uponapplications. Fluid jetting requires the use of a tubular, whether it isjointed pipe (using a rig) or coiled tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of the embodiments of the invention,reference will now be made to the accompanying drawings in which:

FIG. 1 depicts a schematic of a jetting system deployed in a wellboreintersecting a subterranean formation, according to one or moreembodiments;

FIG. 2 depicts a schematic of the downhole tool of FIG. 1, according toone or more embodiments;

FIG. 3 depicts a schematic of an extension drain valve in the downholetool of FIG. 1, according to one more embodiments;

FIG. 4 depicts a schematic of a retraction drain valve and the pistonassembly of FIG. 2, according to one more embodiments;

FIG. 5 depicts another schematic of the retraction drain valve and thepiston assembly of FIG. 2, according to one or more embodiments;

FIG. 6 depicts another schematic of the downhole tool, according to oneor more embodiments; and

FIG. 7 depicts a graph of a stroke signal of the downhole tool of FIG.1, according to one or more embodiments.

DETAILED DESCRIPTION

This disclosure provides a jetting tool for injecting fluid in awellbore intersecting a subterranean formation. Specifically, thedisclosure provides a downhole tool that releases fluid in a cyclicalpattern and can be powered by the jetting fluid or a hydraulic powersource.

Jetting tools are used to perforate the formation by releasing a fluidthrough a nozzle into the wellbore to create a fracture in the formationextending from the wellbore. Moving the jetting tool up and down thewellbore while it releases the fluid can produce a slot in the formationthat runs along the wellbore axis. However, slotting generally is doneby uncoiling and recoiling coiled tubing, which may rotate the jettingtool while it is slotting a perforation in the formation. The rotationof the jetting tool can prevent the slotting to occur in a repeatablepattern, resulting in a malformed, unpredictable shape of the slot.

As described below, a jetting system can include a mechanism that movesthe nozzle in a cyclical pattern without moving the coiled tubing toposition the nozzle. For example, a downhole tool can include a pistonand rod that are powered by some of the pressurized jetting fluid tostroke the nozzle in a cyclical pattern. Thus, a slotted perforation canbe formed in the formation without the unpredictability of moving coiledtubing.

FIG. 1 depicts a jetting system 100 for injecting a fluid into awellbore 20, according to one or more embodiments. The jetting system100 can include a hydraulic power source 10, a carrier 12 in fluidcommunication with the hydraulic power source 10, and a downhole tool200 located on the carrier 12. The tool 200 can be deployed in awellbore 20 intersecting a subterranean formation 30. The hydraulicpower source 10 can include a pump with a fluid reservoir or any othersuitable hydraulic power source to produce a fluid under enough pressureto exit the tool 200.

In one or more embodiments, the tool 200 can be attached to the carrier12, which positions the tool 200 into the wellbore 20 and supplies itwith jetting fluid as indicated by arrow F. The carrier 12 may include,but is not limited to rigid carriers, non-rigid carriers, coiled tubing,casing, liners, etc. The term “carrier” as used herein means any device,device component, combination of devices, media, and/or member that maybe used to convey, house, support, or otherwise facilitate the use ofanother device, device component, combination of devices, media, and/ormember. The carrier 12 can include various cables or control lines, suchas hydraulic control lines, electric control lines, or fiber opticcables. The control lines on carrier 12 can provide a communication datapath or supply power to the downhole tool 200.

The tool 200 can include a housing 201 with extension devices 203 (e.g.,retaining springs, bow springs, or lugs) engaged with the wellbore 20 tostabilize the tool 200 to the wellbore 20 during the fluid injectionprocess. A rod assembly 220 in fluid communication with the carrier 12can be moveably coupled to the housing 201. The rod assembly 220 can bemoveable within the housing 201. Attached to the rod assembly is ajetting assembly 230 housing one or more jet nozzles 231 configured tocontrol the flow of fluid exiting the tool 200. The rod assembly 220 canextend or retract from the housing 201 (as indicated by the arrow S),moving the nozzles 231 away from or towards the housing 201 withoutuncoiling or recoiling the carrier 12 at the surface. Pressurized fluidflows through the nozzles 231 spraying jets of fluid 233 into thewellbore 20 and penetrating the formation 30 forming perforation slots40. The jetting assembly 230 can have any number of nozzles 231,positioned in a variety of patterns along and around the nozzle assembly230. Further, the nozzles 231 can be angled to produce any number ofjets 233 in various angled orientations (e.g., 45 degrees fromperpendicular with the longitudinal axis of the wellbore 20).

In one or more embodiments, the pressurized fluid flowing through thetool 200 can include solid particles (e.g., sand) mixed with a basefluid (e.g., water). The pressurized fluid flowing through the tool 200can include abrasives, acids, chelating acids, polymers, cement,proppant, fracturing fluid, any other chemicals (such as fuel andoxidizers), and combinations thereof. Further, the pressurized fluid caninclude any suitable substance or material that can be injected into thewellbore 20 through the tool 200. In addition, the tool 200 is notlimited to perforating the formation, but can also be used to injectfluid into the wellbore 20 for other stimulation operations, such asacidizing, polymer injection, cementing, hydraulic fracturing, or othersubterranean fluid injection applications. As examples, the tool 200 canbe used to inject fluid to fix leaks in the wellbore 20, such as squeezecementing or in plugging and abandoning operations. In one or moreembodiments, the tool 200 can be employed as a downhole hydraulicfracturing tool.

A travel joint 16 may be coupled between the tool 200 and carrier 12 toallow the rod assembly 205 to move freely within its stroke. Asillustrated, the travel joint 16 is not drawn to scale and may have astroke substantially similar to the stroke of the tool 200. In one ormore embodiments, the carrier 12 can communicatively couple the tool 200to a surface control unit 14 in communication with the hydraulic powersource 10. The surface control unit 14 can include telemetry systems(e.g., modem, transducer, or control lines) and information processingsystems (e.g., a processor). The processor of the surface control unit10 can be configured to perform methods as described herein, such ascontrolling the operation of the tool 200.

A wellbore assembly 18 can be located uphole or downhole from the tool200 in the wellbore 20. Further, an additional wellbore assembly 18 maybe located in the wellbore 20, such as downhole from the tool 200. Inone or more embodiments, the wellbore assembly 18 may be located on thetool 200. The wellbore assembly 18 can include any suitable device (suchas a packer) configured to provide an annular barrier between sectionsof the wellbore 20 to fluidly isolate those sections (e.g., an upholesection 21 and a downhole section 23). In one or more embodiments, thewellbore assembly 18 can include an anchoring device configured toresist motion along the carrier 12, such as unwanted motion in thecarrier 12 produced above the wellbore assembly 18. The unwanted motionin the carrier 12 may be caused by expansion or contraction of thecarrier 12 due to temperature changes in the wellbore 20. Optionally,the wellbore assembly 18 may include the anchoring device without theability to fluidly isolate sections of the wellbore 20.

FIG. 2 depicts a schematic of the tool 200 of FIG. 1, according to oneor more embodiments. The tool 200 can include a housing 201 and achamber 205 in the housing 201. A piston assembly 240 can be moveablewithin the chamber 205. In particular, the chamber 205 can be defined inthe housing 201 by two end caps 207, 209. Further, the end caps 207, 209can include one or more seals 211 to prevent fluid from leaking into orfrom the chamber 205. Seals 211 can include elastomer seals, O-ringseals, annular seals, wiper seals, any other suitable fluid barrier, orcombinations thereof.

The rod assembly 220 includes a conduit 221 that extends through the endcaps 207, 209. The conduit 221 is in fluid communication with thecarrier 12 and includes a flow path for receiving the pressurized fluidand communicating the fluid to the jetting assembly 230.

The piston assembly 240 can include a piston 241 coupled to the rodassembly 220 within the chamber 205 and is moveable with the rodassembly 220. The piston 241 divides the chamber 205 into an extensioncavity 213 and a retraction cavity 215. Further, the piston assembly 240can include one or more seals 211 to prevent fluid communication betweenthe extension cavity 213 and the retraction cavity 215. In one or moreembodiments, the piston assembly 240 may be in fluid communication withthe conduit 221 to channel some of the pressurized fluid to at least oneof the cavities 213, 215 as explained below. Rod actuators 223, 225 mayalso be coupled to the rod assembly 220 to control the flow of fluid outof the cavities 213, 215 as explained further.

FIG. 3 depicts a schematic of an extension drain valve 250 located onthe end cap 207 of FIG. 2, according to one or more embodiments. Theextension drain valve 250 includes an inlet port 251 in fluidcommunication with the extension cavity 213, an outlet port 253 in fluidcommunication with the space outside the housing 201 (e.g., the wellbore20), and a switch device 255 that controls whether inlet port 251 isopen or closed. As illustrated, the drain valve 250 is closed preventingfluid from draining from the extension cavity 213. Thus, the drain valve250 can control the flow of fluid out of the extension cavity 213.

FIG. 4 depicts a schematic of a retraction drain valve 260 located onthe end cap 209, in accordance with one or more embodiments. The drainvalve 260 includes an inlet port 261 in fluid communication with theretraction cavity 215, an outlet port 263 in fluid communication withthe space outside the housing 201 (e.g., the wellbore 20), and a switchdevice 265. As illustrated, the drain valve 260 is open allowing fluidto drain from the retraction cavity 215. Thus, the drain valve 260 cancontrol the flow of fluid out of the retraction cavity 215.

Referring to FIGS. 3 and 4, the switch device 255, which is alsoillustrative of switch device 265, can control whether the drain valve250 is opened or closed by moving to an open position or a closedposition. Although, the discussion is for the switch device 255, thedescription is applicable to the switch device 265 as well. Asillustrated, the switch device 255 is in a closed position and the drainvalve 250 is closed, preventing fluid from draining from the extensioncavity 213. Further, the switch device 255 can be moved to an openposition, opening the drain valve 250. The open position of the switchdevice 255 can resemble the open position of the switch device 265 asillustrated in FIG. 4. That is, in the open position, a portion of theswitch device 255 can be positioned in the extension cavity 213 tocontact the piston assembly 240. In addition, when the drain valve 255is open, fluid can flow through the inlet port 251 from the extensioncavity 213 to the outlet port 253, allowing fluid to flow out of thehousing 201 (e.g., into the wellbore 20).

FIG. 4 also depicts a schematic of the piston assembly 240, according toone or more embodiments. The piston assembly 240 can include a valve270, including an inlet port 271 in fluid communication with the conduit221, an outlet port 273 in fluid communication with the extension cavity213, an outlet port 275 in fluid communication with the retractioncavity 215, and a switch device 277. As illustrated, the outlet port 273is open allowing fluid to flow into the extension cavity 213; and theoutlet port 275 is closed preventing fluid from flowing into theretraction cavity 215 from the conduit 221. The switch device 277 can becoupled to the valve 270 to control which of the outlet ports 273, 275is open or closed. The switch device 277 can be configured to switch aflow path in the valve 270 between the outlet ports 273, 275. In one ormore embodiments, the piston assembly 240 can include a filter 279 influid communication with the conduit 221 and the outlet ports 273, 277.The filter 279 can include any suitable membrane or layer that preventsat least some of the solid particles (such as abrasives, proppant,tracers, cement, polymers, or any other solid particle) in thepressurized fluid from passing through the filter 279 while allowing atleast some of the pressurized fluid to flow through the filter 279. Asan example, the filter 279 can prevent abrasives mixed with thepressurized fluid from entering the extension cavity 213 or theretraction cavity 215. As illustrated, the filter 279 can be positionedin contact with the high flow rate jetting fluid in the conduit 221 toallow the jetting fluid to clean the filter 279 and prevent it fromclogging.

The switch device 277 can control which cavity 213 or 215 is beingfilled by moving from an extension position to a retraction position. Asillustrated, the switch device 277 is in the extension position suchthat the outlet port 273 is open, while the outlet port 275 is closed.In the extension position, a portion of the switch device 277 can be inthe retraction cavity 215 to contact the end cap 209 during the strokeof piston assembly 240. Upon contact with the end cap 209, the switchdevice 277 can be moved to open the outlet port 275 and close the outletport 273. In this retraction position, a portion of the switch device277 can be in the extension cavity 213 to contact the end cap 207 duringthe stroke of the piston assembly 240.

In one or more embodiments, the pressurized fluid flows through theconduit 221 and into the jetting assembly 230. In the illustratedexample of FIG. 4, some of the pressurized fluid is diverted to theextension cavity 213 through the piston assembly 240. As the extensioncavity 213 is filled with fluid, pressure in the extension cavity 213increases, moving the piston assembly 240 towards the end cap 209. Theretraction cavity 215 may contain fluid in it, and as such, this fluidcan be drained through the end cap 209 outside of the housing 201 (e.g.,into wellbore 20). Referring to FIGS. 2 and 4, arrows A-E show exemplaryflow paths of fluid within the tool 200 as the extension cavity 213 isfilled and the retraction cavity 215 is drained by the stroke of thepiston assembly 240. Further, the rod assembly 220 and the jettingassembly 230 can move with the stroke of piston assembly 240.

In cases where upper cavity 213 is being filled with fluid (asillustrated), the rod assembly 220 is moved down through the housing 201and the actuator 223 approaches the switch device 255 of the end cap207. The actuator 223 can be positioned on the rod assembly 220 to closethe extension drain valve 250 when the piston assembly 240 reaches apredetermined position within its stroke (e.g., at the end of itsstroke, half-way through its stroke, 1 inch from the end, or anysuitable position along the stroke of the piston assembly 240). When theactuator 223 contacts or moves the switch device 255, the contact canactuate the switch device 255, triggering the drain valve 250 to openand vent fluid from the extension cavity 213.

As the actuator 223 approaches the switch device 255, the pistonassembly 240 also approaches the switch device 265. When the pistonassembly 240 contacts or moves the switch device 265, the drain valve260 is triggered to close and prevent fluid from draining from theretraction cavity 215. In addition, when the piston assembly 240contacts the end cap 209, the contact can move the switch device 277,triggering the valve 270 to close the outlet port 273 and to open theoutlet port 275. Thus, the stroke of piston assembly 240 can be reversedby opening the drain valve 250, closing the outlet port 273, opening theoutlet port 275, and closing the drain valve 260. During this retractionor return stroke of the jetting assembly 230, the retraction cavity 215can be filled with some of the pressurized fluid flowing through theconduit 221 while the extension cavity 213 can be drained of any fluidthat it contains through the drain valve 250.

To return to the state illustrated in FIG. 4 (i.e., the extension strokeof the jetting assembly 230), the actuator 225 can contact or move theswitch device 265 to its open position, triggering the drain valve 260to open. The piston assembly 240 can also contact or move the switchdevice 255, triggering the drain valve 250 to close. The end cap 207 canalso contact or move the switch device 277, triggering the outlet port273 to open and the outlet port 275 to close.

In one or more embodiments, the switch devices 255, 265, 277 can includeone or more proximity sensors, such as a sonar sensor, an ultra-sonicsensor, an infrared sensor, a magnetometer, an optical sensor, anelectric continuity sensor, or any suitable sensor configured to detectthe proximity or contact between the end cap 207 and the actuator 223,the end cap 209 and the actuator 225, or the piston assembly 240 and theend caps 207, 209. As an example, the proximity sensors may detect whenpiston assembly 240 contacts end cap 209, sending a signal to the valve270 to open the outlet port 275 and close the outlet port 273. Theproximity sensors may also send signals to open the drain valve 250 andto close the drain valve 260. In one or more embodiments, the proximitysensors may detect a predetermined position of the piston assembly 240(e.g., 83% extended or retracted). Thus, the proximity sensors maydetect thresholds of when to control the valves 250, 260, 270. Thesethresholds may be predetermined positions along the stroke of thejetting assembly 230 (e.g., fully extended or retracted, 50% extended orretracted, 2% extended or retracted, etc.). In one or more embodiments,the switch devices 255, 265, 277 can include a biasing device, such as aspring, to adjust the sensitivity of the switch device detecting contactwith at least one of the end caps 207, 209 and the actuators 223, 225.

Referring to FIG. 2, the housing 201 can include a track 217 configuredto guide an azimuthal orientation of the jetting assembly 220. The rodassembly 220 can be moveably coupled to the track 217 through at leastone of the rod actuator 223 and a guide 227 extending from the rodassembly 220. In addition, the jetting assembly 230 can be moveablycoupled to the track 217 through the rod assembly 220. The guide 227 caninclude a wheel, a pin, or a cantilever extension extending from the rodassembly 220 and received in the track 217. In particular, the track 217can be configured to rotate the jetting assembly 230 along its stroke,such as along a helix, a zigzag, or any other suitable rotationalpattern. In particular, the rotational pattern on track 217 can producea corresponding slot in the formation that follows the track 217. Therotational pattern can facilitate fluid injection from various azimuthalorientations of the jetting assembly 230 along the track 217. Further,the rod actuators 223, 225 can form a ring or disk attached to the rodassembly 220 to actuate the switch devices 255, 265 as the rod assembly220 rotates on the track 217. In one or more embodiments, the track 217can be positioned on the rod assembly 220, while a stationary guide 227is positioned on the housing 201 and received in the track 217.

FIG. 5 shows a schematic of the piston assembly 240, according to one ormore embodiments. Optionally, the piston assembly 240 can allow fluid toflow through both the outlet ports 273, 275 (as indicated by the arrowsC and F) without the use of the valve 270. As illustrated, the drainvalve 260 is open allowing fluid to vent through the outlet port 263,while the drain valve 250 is closed. This produces a pressuredifferential between the cavities 213 and 215. The stroke of the pistonassembly 240 can move toward the lower pressure cavity (e.g., the cavity215) in the chamber 205. In addition, the stroke of the piston assemblycan depend partially upon the size of the outlet ports 253, 263, 273,and 275. In particular, the size of the outlet ports 273, 275 can besmaller than the outlet ports 253, 263. In one or more embodiments, thevolume of fluid that exits one of the outlet ports 273, 275 can be lessthan the volume of fluid that exits one of the outlet ports 253, 263.This can ensure that when the outlet port (253 or 263) of the drainvalve (250 or 260) is open, it produces the lower pressure cavitybetween the cavities 213 and 215 to move the piston assembly 240 towardthat open drain valve. Further, without the valve 270, this makes thetool 200 easier to adjust, as it would not depend upon the preciseplacement of the switch device 277. Optionally, the valve 270 can beused to prevent the loss of unnecessary fluid pressure by closing one ofthe outlet ports 273, 275 completely.

FIG. 6 depicts a schematic of the downhole tool 600, according to one ormore embodiments. The downhole tool 600 can be used, as described above,with respect to the jetting system 100 of FIG. 1. Instead of beingpowered by the pressurized fluid flowing through carrier 12 and conduit621, the tool 600 may stroke the piston assembly 640 by filling ordraining cavities 613, 615 with hydraulic fluid from two or more controllines 683, 685. The carrier 12 may provide a communication path for thecontrol lines 683, 685 to the tool 600 from the surface. In one or moreembodiments, the control lines 683, 685 may be in communication with ahydraulic power source (e.g., hydraulic power source 10) and a fluidreservoir located at the surface. The hydraulic power source can also belocated on another downhole tool or on the tool 600. The control line683 may be in fluid communication with the extension cavity 613, whilethe control line 685 may be in fluid communication with the retractioncavity 615. As illustrated, the control line 683 is in fluidcommunication with the extension cavity 613 through a passageway in theend cap 607; and the control line 685 is in fluid communication with theretraction cavity 615 through another passageway in the end cap 609. Asthe extension cavity 613 is filled with fluid from the control line 683,the retraction cavity 615 can be drained of fluid through the controlline 685, moving the piston assembly 640 towards the end cap 609 andresulting in the jetting assembly 630 extending away from the housing601. Alternatively, the extension cavity 613 can be drained of fluidthrough the control line 683, while the retraction cavity 615 is filledwith fluid through the control line 685, moving the piston assembly 640towards the end cap 607 and resulting in the jetting assembly 630 movingtowards the housing 601.

FIG. 7 depicts a graph of an exemplary stroke signal 701 of the tools200, 600 over time. The ordinate represents the percentage of strokerelative to the center of the chambers 205, 605 (e.g., where the pistonassembly 240 is equidistance from the end caps 207, 209); and theabscissa represents time (e.g., seconds). Referring to FIG. 7, positivefifty percent may represent a stroke fully retracted (e.g., the pistonassembly 240 contacts the end cap 207 or the jetting assembly 230 is100% retracted), while negative fifty percent may represent a strokefully extended (e.g., the piston assembly 240 contacts the end cap 209or the jetting assembly 230 is 100% extended). As illustrated, a localmaxima 703 represents a point in time where the stroke of the pistonassembly 240 is about 27.5% of its stroke from the center of the chamber205 (e.g., the jetting assembly 230 is about 77.5% retracted). A localminima 705 represents another point in time where the stroke of thepiston assembly 240 is about 31% of its stroke from the center of thechamber 205 (e.g., the jetting assembly 230 is about 81% extended).

The stroke signal 701 may represent the stroke of the piston assembly240 over time. The stroke of piston assembly 240 and subsequentlynozzles 231 can be configured to move with the stroke signal 701. Inparticular, the stroke signal 701 may be any suitable signal, such as asinusoidal signal that varies in amplitude or frequency over time.Further, the illustrated stroke signal 701 oscillates about the centerof chamber 205, but the stroke signal 701 may instead oscillate aboutany predetermined position along the stroke of the piston assembly 240.A processor may be configured to operate the tool 200 by stroking thepiston assembly 240 according to the stroke signal 701. In one or moreembodiments, the stroke of the piston assembly 240 can be controlled byadjusting the thresholds of the proximity sensors included in the switchdevices 255, 265, 277. Optionally, the stroke of the piston assembly 640can be controlled by varying the hydraulic fluid pumped or drainedthrough control lines 683, 685. In one or more embodiments, the strokeof the piston assembly 240 may be paused or stopped to inject fluid at apredetermined position along its stroke, such as a position where thejetting assembly is 85% extended or retracted.

This discussion is directed to various embodiments of the invention. Thedrawing figures are not necessarily to scale. Certain features of theembodiments may be shown exaggerated in scale or in somewhat schematicform and some details of conventional elements may not be shown in theinterest of clarity and conciseness. Although one or more of theseembodiments may be preferred, the embodiments disclosed should not beinterpreted, or otherwise used, as limiting the scope of the disclosure,including the claims. It is to be fully recognized that the differentteachings of the embodiments discussed may be employed separately or inany suitable combination to produce desired results. In addition, oneskilled in the art will understand that the description has broadapplication, and the discussion of any embodiment is meant only to beexemplary of that embodiment, and not intended to suggest that the scopeof the disclosure, including the claims, is limited to that embodiment.

Certain terms are used throughout the description and claims to refer toparticular features or components. As one skilled in the art willappreciate, different persons may refer to the same feature or componentby different names. This document does not intend to distinguish betweencomponents or features that differ in name but not function, unlessspecifically stated. In the discussion and in the claims, the terms“including” and “comprising” are used in an open-ended fashion, and thusshould be interpreted to mean “including, but not limited to . . . .”Also, the term “couple” or “couples” is intended to mean either anindirect or direct connection. In addition, the terms “axial” and“axially” generally mean along or parallel to a central axis (e.g.,central axis of a body or a port), while the terms “radial” and“radially” generally mean perpendicular to the central axis. The use of“top,” “bottom,” “above,” “below,” and variations of these terms is madefor convenience, but does not require any particular orientation of thecomponents.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentmay be included in at least one embodiment of the present disclosure.Thus, appearances of the phrases “in one embodiment,” “in anembodiment,” and similar language throughout this specification may, butdo not necessarily, all refer to the same embodiment.

Although the present invention has been described with respect tospecific details, it is not intended that such details should beregarded as limitations on the scope of the invention, except to theextent that they are included in the accompanying claims.

What is claimed is:
 1. A downhole hydraulic fracturing tool for use witha fluid, comprising: a housing comprising a chamber, a rod assemblymoveable within the housing and comprising a conduit including a flowpath for the fluid, a piston assembly coupled to the rod assembly andmoveable within the chamber, wherein the piston assembly comprises apiston dividing the chamber into an extension cavity and a retractioncavity, and a nozzle in fluid communication with the conduit andconfigured to control the flow of the fluid exiting the tool.
 2. Thedownhole hydraulic fracturing tool of claim 1, further comprising: acontrol line in fluid communication with the extension cavity, anadditional control line in fluid communication with the retractioncavity, and a hydraulic power source in fluid communication with atleast one of the control lines.
 3. The downhole hydraulic fracturingtool of claim 1, wherein: the piston assembly further comprises a valveincluding an inlet port and two outlet ports, and the outlet portsinclude an extension outlet port in fluid communication with theextension cavity and a retraction outlet port in fluid communicationwith the retraction cavity.
 4. The downhole hydraulic fracturing tool ofclaim 3, wherein the inlet port is in fluid communication with theconduit.
 5. The downhole hydraulic fracturing tool of claim 3, whereinthe piston assembly further comprises a switch device configured toswitch a flow path in the valve between the outlet ports.
 6. Thedownhole hydraulic fracturing tool of claim 3, wherein the pistonassembly further comprises a filter in fluid communication with theconduit and the outlet ports of the valve.
 7. The downhole hydraulicfracturing tool of claim 1, further comprising a track and the nozzle ismoveably coupled to the track.
 8. The downhole hydraulic fracturing toolof claim 8, wherein the track is configured to rotate the nozzle alongthe stroke of the nozzle.
 9. The downhole hydraulic fracturing tool ofclaim 1, wherein: the chamber includes an extension drain valve and aretraction drain valve, the extension drain valve controls the flow offluid out of the extension cavity, and the retraction drain valvecontrols the flow of fluid out of the retraction cavity.
 10. Thedownhole hydraulic fracturing tool of claim 9, wherein: the rod assemblyincludes an extension actuator and a retraction actuator, the extensionactuator is positioned on the rod assembly to open the extension drainvalve, and the retraction actuator is positioned on the rod assembly toopen the retraction drain valve.
 11. A method of jetting fluid,comprising: flowing fluid through a conduit; moving a piston dividing acavity and an additional cavity; and releasing the fluid through anozzle in fluid communication with the conduit and coupled to thepiston.
 12. The method of claim 11, further comprising: channeling someof the fluid into the cavity; venting another fluid from the additionalcavity.
 13. The method of claim 11, further comprising: filling thecavity with another fluid through a control line; and draining theadditional cavity through an additional control line.
 14. The method ofclaim 11, further comprising moving the nozzle according to a strokesignal.
 15. The method of claim 11, further comprising rotating thenozzle.
 16. The method of claim 11, further comprising closing a drainvalve in fluid communication with the cavity.
 17. The method of claim11, wherein the channeling further comprises filtering the some of thefluid.
 18. A jetting system, comprising: a carrier; and a jetting toolin fluid communication with the carrier, comprising: a housingcomprising a chamber, a rod assembly moveable within the housing andcomprising a conduit including a flow path for fluid, wherein the pistonassembly comprises a piston dividing the chamber into an extensioncavity and a retraction cavity, a piston assembly coupled to the rodassembly and moveable within the chamber, and a nozzle in fluidcommunication with the conduit.
 19. The jetting system of claim 18,wherein: the piston assembly comprises a valve including an inlet portand two outlet ports, and the outlet ports include an extension outletport in fluid communication with the extension cavity and a retractionoutlet port in fluid communication with the retraction cavity.
 20. Thejetting system of claim 18, further comprising: a hydraulic powersource, wherein the carrier comprises: a control line in fluidcommunication with the extension cavity, and an additional control linein fluid communication with the retraction cavity, and wherein thehydraulic power source is in fluid communication with at least one ofthe control lines.